Many prior art inventions have been directed to the processing of slurries, fluidized beds, and the like, and especially to the separation of fine particles, sometimes called "fines", from a mixture of such particles and a fluid, for example as a slurry of fine particles in a fluid in which the particles are suspended. It is sometimes desired to remove from particles any film or coating on the particles suspended in a fluid by washing away the material of the film or coating with the fluid from which the particles have been separated. It is also sometimes desired to remove soluble components from particles by leaching the components into a surrounding fluid. Another need which occurs frequently is to contact fluid reactants with catalyst particles for the purpose of promoting chemical or biochemical reactions. Further desires are to be able to pump mixtures of particles and fluid, and to conduct particle formation and growth, such as in crystallization.
Among this prior art is the process and apparatus disclosed in co-pending U.S. patent application Ser. No. 319,132, of Robert J. Adler, filed Nov. 9, 1981, and the following published articles, copies of which are being supplied under Patent Office Rule 1.56.
1. Article in "Chemical Engineering" for November, 1953, pages 212-213.
2. Article in "Chemical Engineering" for June, 1955, pages 234-238.
3. Mori, Y., et al., "On the Characteristics of a Centriclone" Chem. Eng. Japan 22, 7 (1958). accompanied by nine pages of handwritten translation into English.
4. Description of cyclones and "Dyna Whirlpool", pages 350 to 356, Mineral Processing Technology, 3rd Edition, Pergamon Press (1985).
5. Klumpar, I. V., et al., "Air Classifiers", Chemical Engineering, Mar. 3, 1986, pp. 77-92.
The prior art devices are primarily directed to separation and are not suited to the simultaneous performance of the other functions listed above, which are generally performed by other means. Moreover even the prior art separation apparatus suffers from a number of disadvantages. For example, in the typical centriclone, the slurry must often be pumped in at high speeds, causing wear upon the pumping apparatus, the centriclone, especially its impeller and impeller region, and/or the particulate matter. Wear on apparatus is a problem when the particulate matter is sharp silica or the like; conversely, the centriclone separation process is destructive of softer particles, which may make further concentration or processing difficult.
Another disadvantage of prior art devices is that they are not self-pumping and require external pumps in inflow and/or outflow streams. These additional pumps represent complexity and are subject to wear when abrasive particles are being processed.
There is a need for apparatus which avoids the various disadvantages of the centriclone and similar separation devices, which is simple and robustly constructed, subject to minimum wear, causes minimal particle attrition, is self-pumping, and can be adapted to perform a variety of processing tasks.